Tuesday 24 June 2014 08.52 EDT
First published on Tuesday 24 June 2014 08.52 EDT

The judges of the UK's top prize for children's literature, the Carnegie medal, have rallied in the face of an extraordinary attack on the winning novel from the Telegraph, which called Kevin Brooks's The Bunker Diary a "uniquely sickening read" which "seems to have won on shock value rather than merit".

Brooks was named winner of the Carnegie on Monday, joining a long roster of prestigious winners which includes Arthur Ransome – who won the first ever award in 1936 – Alan Garner, Penelope Lively and Philip Pullman. The Bunker Diary, which was turned down by publishers for years because of its bleak outlook, is told in the form of the diary of a kidnapped boy held hostage in a bunker. Awarding him with the medal, judges said he had created "an entirely credible world with a compelling narrative, believable characters and writing of outstanding literary merit".

But writing in the Telegraph, in a piece headlined "why wish this book on a child?" and describing The Bunker Diary as "a vile and dangerous story", literary critic Lorna Bradbury vigorously disagreed.

She called the book "much nastier" than other dystopian fictions such as The Hunger Games and Divergent, writing: "Here we have attempted rape, suicide and death by various means, all of it presided over by our anonymous captor, the 'dirty old man' upstairs who it's difficult not to imagine masturbating as he surveys the nubile young bodies (including a girl of nine)."

Saying that the novel "makes versions of the imprisonment narrative for adult readers, such as Emma Donoghue's Room, based on the case of Josef Fritzl, the Austrian who locked up his daughter for 24 years, look tame", Bradbury questioned whether books like Brooks's were "good for our teenagers".

"There's nothing on its cover to alert readers – or parents – to the nastiness of its subject matter. There's no warning attached; not even a young adult specification, which is normally used to flag up books that have adult content. And the fact that this is now the winner of the Carnegie medal will mean that it will be read by more teenagers still," wrote Bradbury, asking if the Carnegie should really "champion this kind of book".

The Carnegie, which is judged by librarians, moved quickly to defend its choice. Helen Thompson, hair of the CILIP Carnegie judging panel this year, said that The Bunker Diary was "absolutely the book Carnegie should be championing – superbly well-written, atmospheric, and loved by readers", and that it was "being devoured by young people across the country".

"Published as a young adult novel, not a children's book, The Bunker Diary is clearly aimed at an older audience, as can be seen from both the cover, and the description on the back of the cover. Age or 'warning' stickers are misleading and condescending – although I'm sure the publisher would be thrilled to have a warning sticker. Sales would go through the roof," said Thompson.

Judges, she said, were not considering "shock value" when selecting their winner. "The CILIP Carnegie judging process is transparent and based entirely on the criteria. At no point do the judges consider 'shock value'. We pride ourselves on basing all judgments on literary quality alone – as can be seen from the outstandingly well-written winner of the 2014 award," said Thompson, adding that the book is "full of hope", and contains "many instances of humanity, love, community, support and forgiveness. Incredibly well-crafted, it is indeed a master storyteller who can leave the reader with such a feeling of hope even when the ending is not a traditionally happy one."

Brooks himself pointed out that "young people are wise enough, if they are watching or reading something they don't like, to stop doing it. They are not idiots."

"I've got no problem with anyone having their opinion, but this just doesn't stack up," he said of Bradbury's attack. "The Bunker Diary is a book about dark and disturbing subjects – it has to contain dark and disturbing things. And it is aimed at teenagers, who I know from personal experience are perfectly capable of dealing with that."

Teenagers, said the author, "are surrounded 24 hours a day by far worse stuff on the news. I'm not writing about this in a provocative, gratuitous, glamorising way – it's all written about realistically and thoughtfully. And I disagree that it lacks redemption – yes it doesn't have a happy ending, but within the story there is genuine kindness and love and protection, and if that is not a positive look at how humans can behave in a desperate situation, I don't know what is."

At the Carnegie ceremony, Brooks had said that "children – and teens in particular – don't need to be cosseted with artificial hope that there will always be a happy ending. They want to be immersed in all aspects of life, not just the easy stuff. They're not babies, they don't need to be told not to worry, that everything will be all right in the end, because they're perfectly aware that in real life things aren't always all right in the end."

Children's librarian Beth Khalil told the Guardian that while she wouldn't let her year seven or year eight students read The Bunker Diary, "our year nine girls loved it and did not then come to me to complain about content or the unsuitability of it. They were more concerned about letting me know how much it had moved them and how powerfully frustrated and moved they were by the ending."